Exhaust gas catalyst system

Abstract

An exhaust gas catalyst system for a vehicle, for treating fine dusts of exhaust gases produced by an internal combustion engine group of the vehicle, having an inlet duct and an outlet duct connectable to the internal combustion engine group and to a diesel particulate filter (DPF) system. A hollow main body extends along a main axis (X-X) between a head wall having an inlet opening and an outlet opening, and a bottom wall and defines a gas treatment chamber having a first chamber fluidically connected to the inlet opening and a second chamber fluidically connected to the outlet opening. The first and second chambers are fluidically connected in a region proximal to the bottom wall so exhaust gases flow in the first and second chambers in opposite directions. Exothermic filtration and oxidation operations are carried out on the fine dusts by a catalyst substrate housed in the second chamber.

1 . An exhaust gas catalyst system of a vehicle, comprising an internal combustion engine group and a diesel particulate filter (DPF) system, wherein said exhaust gas catalyst system is suitable for performing treatment operations of fine dusts of exhaust gases produced by said internal combustion engine group, said exhaust gas catalyst system comprising:
 an inlet duct fluidly connectable to the internal combustion engine group to receive the exhaust gases;   an outlet duct fluidly connectable to the DPF system connected to the environment; and   a main body which extends in length along a main axis (X-X) between a head wall comprising at least one inlet opening fluidly connected to the inlet duct and at least one outlet opening fluidly connected to the outlet duct, and a bottom wall;   wherein the main body is hollow and internally defines a gas treatment chamber, said gas treatment chamber comprising a first chamber fluidly connected to the at least one inlet opening, and a second chamber, fluidly connected to the at least one outlet opening, said first and second chambers respectively having a radially distal development with respect to said main axis (X-X) and a development along the main axis (X-X), wherein the first chamber and the second chamber are separated from each other by a separation wall;   wherein the first chamber and the second chamber are fluidly connected in a region proximal to the bottom wall, such that flows of the exhaust gases in the first and second chambers are in counter-flow along the main axis (X-X); and   wherein the exhaust gas catalyst system further comprises a catalyst substrate through which exothermic filtration and oxidation operations are performed on the fine dusts present in the exhaust gases, said catalyst substrate being housed in said second chamber.   
     
     
         2 . The exhaust gas catalyst system of  claim 1 , wherein the first chamber is an annular chamber having distal development with respect to said main axis (X-X) and the second chamber is a central chamber having development along the main axis (X-X), wherein said central chamber is entirely or at least partly surrounded by the annular chamber, and wherein the annular chamber and the central chamber are mutually separated by a separation wall which extends along the main axis (X-X) and are fluidly connected in a region proximal to the bottom wall, in such a way that the flows of the exhaust gases in the annular and central chambers are in counter-flow along the main axis (X-X), wherein in the passage between the annular chamber and the central chamber the flows of the exhaust gases are in a radial direction from outside to inside. 
     
     
         3 . The exhaust gas catalyst system of  claim 2 , wherein the central chamber comprises a catalyzing region axially proximal to the bottom wall and a bottleneck positioned between the catalyzing region and the at least one outlet opening, wherein said bottleneck hinders outflow of the exhaust gases, prolonging crossing time in the catalyzing region. 
     
     
         4 . The exhaust gas catalyst system of  claim 2 , wherein the annular chamber defines a fluidic conduit for flow of the exhaust gases in which the exhaust gases flow undisturbed and are subjected to heating operations due to higher temperatures produced in the central chamber. 
     
     
         5 . The exhaust gas catalyst system of  claim 1 , wherein the bottom wall has a shape that facilitates the flow of the exhaust gases from the first chamber to the second chamber. 
     
     
         6 . A vehicle comprising an internal combustion engine group, a diesel particulate filter (DPF) system, and an exhaust gas catalytic system according to  claim 1 , wherein said exhaust gas catalyst system is upstream fluidly connected to said internal combustion engine group and downstream fluidly connected to said DPF system. 
     
     
         7 . The vehicle of  claim 6 , wherein said vehicle is a tractor or a specialty tractor. 
     
     
         8 . A method for treating exhaust gases of a vehicle, wherein said exhaust gases are produced by an internal combustion engine group of the vehicle, and wherein said vehicle comprises a diesel particulate filter (DPF) system, said method comprising:
 fluidly connecting an exhaust gas catalyst system suitable for performing treatment operations of fine dusts of the exhaust gases produced by said internal combustion engine group to the internal combustion engine group and to the DPF system, said exhaust gas catalyst system comprising:
 an inlet duct fluidly connectable to the internal combustion engine group to receive the exhaust gases; 
 an outlet duct fluidly connectable to the DPF system connected to the environment; and 
 a main body which extends in length along a main axis (X-X) between a head wall comprising at least one inlet opening fluidly connected to the inlet duct and at least one outlet opening fluidly connected to the outlet duct, and a bottom wall; 
 wherein the main body is hollow and internally defines a gas treatment chamber, said gas treatment chamber comprising a first chamber fluidly connected to the at least one inlet opening, and a second chamber fluidly connected to the at least one outlet opening, said first and second chambers respectively having a radially distal development with respect to said main axis (X-X) and a development along the main axis (X-X), wherein the first chamber and the second chamber are separated from each other by a separation wall; 
 wherein the first chamber and the second chamber are fluidly connected in a region proximal to the bottom wall, such that flows of the exhaust gases in the first and second chambers are in counter-flow along the main axis (X-X); and 
 wherein the exhaust gas catalyst system further comprises a catalyst substrate through which exothermic filtration and oxidation operations are performed on the fine dusts present in the exhaust gases, said catalyst substrate being housed in said second chamber; and 
   allowing the exhaust gases produced by the internal combustion engine group to flow into the first chamber and then into the second chamber, so that catalyzing operations are carried out in proximity of the at least one outlet opening in direction of the DPF system.   
     
     
         9 . The exhaust gas catalyst system of  claim 2 , wherein said bottom wall is curved or shaped to direct the exhaust gases from the annular chamber to the central chamber.